The possible involvement of hydrogen peroxide or other reactive oxygen intermediates in the regulation of glucose transport activity will be studied in this project. Hydrogen peroxide production by cells exposed to a number of transport stimulating agents will be assessed using luminol chemiluminescence as an assay technique. In addition, cells made deficient in glutathione peroxidase will be tested for their sensitivity toward various transport stimulating agents. In this way, we hope to determine if hydrogen peroxide stimulates transport directly or through its effects on cellular NADP levels.